While the rest of us are taking down the Christmas decorations, the astronauts on the International Space Station are still waiting for their presents – and Elon Musk's SpaceX rocketeers plan to fire them into orbit on Tuesday, weather permitting.
This resupply mission will try to haul up some of the cargo that should have …

Re: > make the descent while SpaceX's landing barge gets into position

I'm wondering what odds the poor little barge has got. If the rocket has a 50/50 chance of successfully landing, that is quite a big chance of missing the target altogether, added to another chance of hitting the target and going KA-BOOM! Is the barge KA-BOOM-proof?

Re: Is the barge KA-BOOM-proof?

Disappointed, I am.

After looking at the clickbait headline I was hoping this launch would precede one with sharks and lasers. Or maybe it might have something do with testing a cat to see if it lands on it's feet when tossed in zero-gravity. Oh well... it's after beer-o'clock here.

Re: Disappointed, I am.

Not quite, but if the launch fails in the "going up" phase (let's hope it doesn't) than at least some sharks stand some chance at acquiring a brand new laser - one with 5000 shots per second, no less! We'd be doomed! Doomed, I tell ya!

Re: Scrubbed...

"This mission was aborted just two minutes before launch after an unspecified problem was discovered in the rocket’s second stage and scrubbed for the day. Due to the narrow window for launch determined by the International Space Station’s orbit, the next opportunity for lift-off is this Friday, January 9, 2015."

"In 1971, Jean Peters and Howard Hughes divorced after a 14 year marriage. She agreed to a lifetime alimony payment of $70,000 annually, adjusted for inflation, and she waived all claims to Hughes' estate."

So, why are they specifically trying to land the first stage (which seems like an incredibly difficult proposition)? Couldn't they use parachutes (and possibly landing rockets) and floats to get it in the ocean intact and then go pick it up?

I don't know if it's the reason, but I really wouldn't want to re-use a booster stage that had actually been in seawater rather than just exposed to airborne salt sprays. One of the things I had to do every quarter whilst shipboard or stationed shoreside was a sonic cleaner dip and high-pressure air dry on my computers, otherwise the damn solder joints would corrode. Obviously not Navy MILSTD. [There's a reason that painting a ship is a continuous process and that's it. Turn your back and rust spontaneously recurrs.]

They don't want to drop it in all that horrible corrosive salt water. Or come to think of it, bang it into that nasty water, it doesn't compress so it's surprisingly hard and the top keeps on wobbling about. It's also expensive to have recovery fleets to pick stuff up.

SpaceX is all about re-usability and low cost. The Dragon capsule can land on land. I don't think the current one is reusable though, as they're still playing with the reusable engines for the man-rated capsule. That will land on land, and will be re-usable. Those engines also are supposed to be able to fire up quickly, so the capsule doesn't need an escape tower to whisk the astronauts off in case of a pad explosion. And they're supposed to be re-usable for wandering around space, and for the de-orbit burn, and to land the capsule on the Moon and get it back off again. Although I'd imagine there'll be a few trips to the ISS and re-designs before they try that.

So I guess the same goes for the rocket. They've already tested the landing stuff with their Grasshopper test rocket. So as you might struggle to slow an unweildy rocket from hypersonic speed with parachutes without bending it, or causing it to tumble - and it's got rocket motors anyway, why not use those. And seeing as they've solved the problem of landing a rocket, why not do that too. Particuarly as if you use a parachute you might bend the thing when it hits the ground too. At which point it costs so much to re-furbish it before re-use that you may as well not bother. Like the Shuttle solid rocket boosters. You need re-usable engines in order to re-use the rocket, so none of this should be an extra problem - and parachutes are probably not much ligther than the extra fuel needed anyway.

The landing is in water now, so if they screw up and crash the rocket, it won't land on anyone's head. Eventually the plan will be to take of from Canaveral, and land right back there ready for servicing and re-use. I'd imagine they've got to hit the barge a few times before the FAA will certify them.

The reason for returning to land is salt water is hell on the engines and other components, it would need expensive maintenance after every splashdown, possibly more expensive than just ramping up the production of new cores. They looked into parachutes first but determined it was not going to work for their needs.